Polar h1 is stylish, slim and very comfortable. It comes along with chest strap. It is a sensor and not a monitor. This, it doesn’t include the wrist watch. Most of the polar heart rate monitors comes with h1 heart rate sensor. The h1 heart rate sensor is proven to be accurate. It can transmit data under water too. So good choice for swimmers. It has user replaceable lithium battery. It’s a value for money device.